TNT-Audio Readers' Corner
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Loudspeaker MDF fix
Hi Mark,
I read part 2 on cabinet walls. You mention a way to fix my dead sounding mdf cabinets but I have not run across the solution reading through the other parts. Did I miss it?

You described the sound of my cabinets perfectly, dead with somehow a less than dead midrange! Glad I spent two months on them. They tick most of the audiophile boxes but all it takes is to put on any say Southern Rock or mainstream music we have all heard a million times and it’s obvious more is missing than the usual cabinet vibrations.

I'm probably going to start all over and follow your advice on the thinner damped birch ply construction. It works for Harbeth and just makes more sense to have a good sounding cabinet first and then knock down any specific frequency peaks with bracing or damping. I'm going to play with some eqqualisation first but not expecting that to be the cure. Love to hear your latest thoughts on the subject.
Todd - E-mail: tcorrigan1984 (at)

Hi Todd,

Good to hear from you!
You win this week's prize for spotting when I promise another article but then it doesn't appear for years or even decades.

I am very pleased that you hear a similar effect from MDF that I do. With qualitative reporting, one experience is an anecdote, many similar experiences add up to useful data. Interestingly I particularly notice the effect with material like Little Feat and the Allman Brothers and funk fusion, perhaps because of the percussion, micro transients or the complexity and density of the material.

The solution is exoskeletal and works with various materials. I have successfully used relatively thin Baltic birch plywood glued to the outside of existing mdf cabinets with great success. The adhesive is really important. PVA type white glues do not give good results and I have even caused the cabinets to delayer with heavy bass! 2 pack adhesives like Aerolite 306 (and similar) are much more successful.

A recent experiment (with a chipboard cabinet, which tend to be better than mdf) was very successful using hardwood flooring. This was the solid hardwood decorative type, not the engineered veneered type. Because it interlocks, it is possible to use flexible adhesive (like PVA white glue) between the adjacent planks while using 2 pack (as above) to affix the flooring to the original mdf cabinet. This results in the cabinet walls behaving like smaller cabinets. Otherwise just slather the cabinet and the joints with 2 pack adhesive (take care to follow the safety instructions scrupulously) and cover the sides, back, top and bottom with the extra layer of hardwood.

Radius the corners to reduce diffraction and prevent a shift in the baffle step frequency. The hardwood flooring comes in various thicknesses from about 6mm to 12mm and birch plywood likewise. If it is possible to get into the cabinets (sometimes working through the driver apertures like a keyhole surgeon) adding hardwood braces inside is very useful.

I will get around to writing this up properly one day. Please keep me posted with your progress and do not hesitate to ask me for any more information. Good luck with the project and Happy Listening!
Mark, The Old Scribe
Mark Wheeler

Soundsmith SMMC1 loading design
I have an SMMC1 and enjoyed reading through your testing and listening thoughts on how best to optimize it. The problem is I am an idiot and cannot read your diagram showing how to achieve 2300pF loading at stock 47k/100 at the pre amp. Would you mind taking a moment to put it into layman's terms what I need to achieve such a result?
Thank you,
James - by e-mail

[Zobel loading]

Dear James,
it is pretty simple: at the right there's the phono preamp input section load, that you can't change (47k/100), while at the left there are two Zobel networks that you have to add, for example inserting them into the RCA plugs at the end of the phono cable (or inside a small metallic box, if necessary). The first Zobel network consists of a resistor and a cap connected in series (i.e. one after the other). The resistor is, again, a 47kOhm, while the cap has a value of 10nF. Then you have a second Zobel network, with a 1kOhm resistor connected in series with a 1nF cap. The two horizontal lines are, of course, the negative and the positive runs of the wires. If still in doubt, ask a technician to build this scheme for you, it takes less than 30 minutes to build it. Of course, I'm assuming your preamp has a standard 47kOhm/100pF input load.
Hope this helped somehow,
Lucio Cadeddu

inDiscreet linear preamp???
Dear Giorgio,
I came across your article about inDiscreet Phono Preamp. I have built this preamp and was really satisfied with it. I really like the sound and the dynamics of it. I was so trilled that I wondered if it is possible to modify this phono preamp to linear preamp. For testing purposes I have removed RIAA filter and changed collector resistances to lower the gain of the first stage. I didn't change the gain of second stage because I wasn't sure about influence of gain and positive feedback on the stability of preamp. It worked with very small signals but showed distortion at larger signal voltages.
I am just a small DIYer and I really don't have good equipment to test and design preamp from scratch so I was wondering if You can tell me what do I need to change to modify it to good linear preamp.
Best regards,
Zvonimir - E-mail: zmalovic666 (at)

Hi Zvonimir,
I am very happy you like indiscreet. To reduce the gain the simplest solution is just to increase the value of R14 and R15 (the two resistor must always have the same value). Should the gain still be too high, you can increase the value of R4 and R5 too.
This increases negative feedback, and reduce gain. Note that it is an in-place feedback, that is the inverted signal is not brought back to a previous stage and summed with the original one, so it cannot do much damage, but it might reduce dynamics a little.
The best solution would probably be to:

Hope this helps,
Giorgio Pozzoli

Sorry, no LP sounds better than CD
You all are just being snobs, period. Music is music, and most of your vinyl is mastered from cd originals. Jejejejejejeje!
There is nothing warmer about black plastic.
I did get some good references for some music. I have forgotten about Steely Dan.
So, yes, you like vinyl better but than does not mean anything to anyone else. Jajajajaja...
(Did you understand my laughing at you in Spanish?...jejejejejeje!)
Frank - E-mail: fllenas (at)

Dear Frank,
year 2021. And are we still flogging this dead horse? Seriously? Clearly, the Covid19 virus has been more harmful than expected, as it affected many vital organs (not only lungs, evidently). I don't know if there's a cure for this, but getting a life might be a good place to start.
Hope this helped somehow,
Lucio Cadeddu

Mosfet unknown bias value question!
Hi Dejan! I was reading your article about Bias. Wow lot of precious knowledge there, thanks.
I have just repaired a H&H power amplifier (MOSFET) opened resistors on the offset circuits (circled in red in the picture).
The offset is easy to understand, no load and signal voltage at output but I am clueless on how to adjust the bias on this monster of a circuit.
How would you do it? I see that someone in the schematic as circled the g1 and g2 of the transistors but since no value is showed, I am lost! (lost and clueless haha!).
Thanks in advance for any help or pointer!
Sorry for the bad schematic it is all i could find. The power transistors are 2sk135/2sj50.
Nicolas - E-mail: zenithaudio2003 (at)

Dejan is no longer in touch, so Lucio has forwarded me your email.
As far as I can see the amplifier is a push pull design. The bias setting in theses cases is normally used to achieve the expected behaviour (that is A or AB class) and minimize crossover distortion. In theory and principle this could be done setting the bias trimmer halfway, applying a variable amplitude sine wave to the input, and then moving the setpoint around trying to minimize the output distortion; however in a Class A the setting must be such that both banks are both on at the same time, while in a Class AB with small input signals both banks must be on but with large signals only one bank must be on at a time. The problem is that we have no clue if this is a class A or AB amplifier.
Actually, in general, the designer supplies information about the specific setup procedure to be followed.
Hopefully the bias setting might have a very limited effect, so that any trimmer position is safe, but this is not sure at all, and with this kind of power beasts you cannot work by trial and error: any mistake could completely destroy the MOSFETs in a far less then a tenth of a second. Also, if you are sure that the bias trimmer has not been moved around, you could also assume it is in a safe position, but this too is not sure at all, as you changed a few components.
So the safest suggestion I can think of is to find another board of the same type, measure the gate voltage and try to reproduce the same situation, as a start point. But even this is not so safe, in the end.
Happy listening,
Giorgio Pozzoli

Re: Question about playing 78's on ordinary 33/45 turntable
Hello, David,
Thanks for your very helpful reply. It's what I expected and I won't risk damage to the cartridge (it's an Ortofon MC 15 super). I have another (old) turntable, that I don't use, with a Shure M75ED cartridge but it also only has speeds of 33 and 45. So I suppose I can just keep the records as a curiosity. I bought them in a charity shop in Dublin for 20 euros.
Best wishes,
James - E-mail: j.hamilton (at)

Hello again,
Thanks very much for the photos--that should be a lovely set, and I wish you had better facilities for playing it. I can say that the Shure cartridge, if outfitted with a "78 RPM" (i.e., large profile) stylus, would be a fine choice for playing shellac records. Some have claimed success dubbing to computer at a slower speed and then compensating in software; perhaps that approach would work for you, but I have no experience with it, and hence no advice to offer. If you do explore it, I'd love to hear about your adventures. Alternatively, keep your eyes open at thrift stores and yard sales for something like an old Dual with 78 speed; you could transplant the Shure to it and be off to the races.
I don't own a copy of your set on 78s, but I do have a World Records LP reissue, and for what it's worth, the jacket indicates this recording dates to 13 November 1933. Note, that's late enough that it should actually run at 78 RPM, no need to worry about pitch control as long as you have the nominal set point. I'll also note that a few years back Tully Potter wrote a highly regarded two-volume biography of Adolf Busch (the quartet's founder and namesake) that, I'm told, is well worth reading. Unfortunately, it slipped out of print before I got my act together to buy a copy, and available copies now tend to be, shall we say, very dear, but you might be able to scare one up at your local library.
Happy listening,
David Hoehl

Zero Zone HIFI Split Nap250
Hello Lucio,
You may recall me writing regarding my purchase of the Zero Zone Class D mono's that you recently reviewed. AliExpress were promoting another Zero Zone product, their Nap 250 amp. Well I was tempted and curiosity got the better of me I am now the owner of this amp. I have to say that I actually prefer it to their Mono's. I don't know how they do it for 126UKP. The cases alone would cost more here in the UK.
This amp is one to watch and hear in your system!
Michael - E-mail: michael665booth (at)

Dear Michael,
I'm quite familiar with the original Naim NAP 250, having owned two of them. And I'm 100% sure the Class D ZeroZone monos performs way better, no doubt about this. Perhaps the NAP250 clone they make is better than the original NAP250, it could be! I'll take your word for it. And thanks for the precious feedback, now you made me curious :-)
Happy listening,
Lucio Cadeddu

Linn Akito arm rewiring
Hello, Roger. I read your article in TNT-Audio magazine about the repair of the Linn Akito tonearm. The article is very interesting and informative. I have a Linn Axis vinyl disc player with an Akito tonearm. The tonearm works well, but I want to improve the sound quality and change the wires inside the tonearm. Please write how I can do this. Thank you for reading my letter.
Arkadij - E-mail: smirnovarkadij (at)

Arkadij, thanks for your email.
As I review my disassembly process for the Akito tonearm I have come to the realization that just changing the wiring may be done with a lot less trouble than what I did. It probably isn't necessary to separate the armwand from the yoke. I started by removing the DIN connector from the bottom of the base. This automatically broke the internal wires. I suggest that you try doing this starting at the headshell instead. Apply some heat to the headshell connector in order to loosen it enough to pull it out. Be careful, too much heat may damage the paint finish. Cut or unsolder the wires from the headshell connector and immediately attach a string or small wire to the old wires. This string will remain inside the armtube and act as a pull string for threading the new wires. It will have to be a very thin string or wire in order for this to work.
Once this is done you can remove the DIN connector from the bottom of the base and the old wires will come out with it. Now comes the hard part, you must solder the tiny, new wires to the DIN connector. Not as easy as it sounds, it takes some experience to solder these wires. If you don't have experience soldering very small wires you will need to get some help to do this step. Copy the colour code of the old wires or look up the connection drawing on the internet. It is the standard DIN phono connector drawing that you need. Be careful, you will be soldering from the inside and the drawing you pull up may show the connector pins from the outside! Next, all you have to do is attach the new wires to the pull string and thread them through the arm. I suggest that you cut to length only after they are threaded in the tonearm. The wires need to make a sharp turn as the leave the base and thread into the armwand and this may be difficult to accomplish. In the worst-case scenario you may need to pull the wires back out, detach the armwand from the yoke, and try again. The procedure for that is in my original article. Note that I didn't reuse the headshell-end connector as it was too damages from the heat used to remove it. In any case the pins are very tiny and very close together. I simply soldered connectors to the ends of the wires and left them loose in the armtube. That's it, I have not tried this specific sequence of steps butI think that it should work fine.
Hope this helped somehow,
Roger McCuaig

Mysterious loudspeakers
I have a set of Cliffhanger speakers. They have no markings other than someone wrote “jumper” with a pencil on the bass cabinet. There is not even any markings for + or -. They have mounts for grills but they did not ever have any that I have seen in pictures ever for this model. They are finished on all surfaces, even the bottoms. Wondering if maybe they were a prototype? I am located in British Columbia, Canada.
Yours truly,
Matthew - E-mail: kootenayhifi (at)

Dear Matthew,
your loudspeakers seem to be the Cliffhanger Audio Systems model CHS-2/W-2, a pair of standmount monitors coupled with a standalone subwoofer unit. They retailed for 3,300$ in 1999/2000 and they have been positively reviewed by Soundstage magazine. As for markings for positive or negative connectors, consider that, generally, the positive one is placed on the right, when looking at the loudspeaker from behind.
Hope this helped somehow,
Lucio Cadeddu

Cairn amplifiers
I have been finding a lot of reviews and some information on Cairn amplifiers on your website. I bought recently a Cairn K1 HE mono block, and also Cairn MEA 500 CAPA and I like them so much I want to build a (vintage) Cairn system.
I find however no information on these amplifiers as Cairn does no longer exist. Do you know, or can you provide, any data (and manuals?) of these amplifiers? Or do you know how I could contact the former Cairn company owners?
I find some information online, but it seems like people copy each other. I want to buy a Cairn K3 HE for example, but according to specifications I find online they have about the same output as 2 K1 mono blocks, but 1 K1 costed as much as 1 K3 back then (2490 Lira). Which I don't understand, so not sure if the specifications I find are even correct.
It is a beautiful product, for reasonable prices, a real pity they do not exist anymore.
Stanislas - E-mail: stanislasdenijs (at)

Dear Stanislas,
unfortunately I can't supply any other info except the ones you can find in our reviews of the Cairn components. It's a pity the company is no longer active, as their products were certainly well made and good sounding. As for manuals, you can find some of these at the usual library HiFiengine (you might need to register to log in). I've had a look and found the manuals for the following components: Cairn KO-3 3-Channel Power Amplifier, Cairn KO-5 5-Channel Power Amplifier, Cairn KO-2 Stereo Power Amplifier, Cairn Fog Compact Disc Player. Registered users can download these manuals for free.
On a side note, let me say that I'm always a bit worried when someone decides to buy products of a company that does no longer exist: spare parts and service might be a serious problem. Think about that.
Hope this helped somehow,
Lucio Cadeddu

Why not use BNC terminated coax for low-voltage audio interconnects?
Hi Giorgio,
I was reading your article on the DIY passive pre-amp. For the life of me, I do not understand why audio nuts don't make better use of available interconnects, always using RCA, when BNC is much more secure, and coax, which is very noise resistant. Instead I read of pseudoscience claims that contain a morsel of truth, and built upon it is a crackpot theory. I deal a lot with analog electronics, mostly DC, and I regularly integrate pro-audio parts into my designs. But I use whatever is best for the given application. I use 10 awg microstranded, tinned copper, silicone insulated conductors terminated by pro-audio gold-plated banana plugs designed for loudspeaker connections.
I end up with 1 milliohm/ft. impedance at 0-10 Hz. Considering I'm chasing 10th's of microvolts, these test leads are indispensible. But I also use BNC CONNECTORS in noisier conditions, or where I need switching, such as with a Breakout box on a multiplexer. I use gold-plated stuff only in consideration of long-term use. Gold is the 3rd best conductor. But it's practically inert. So, over time it will be the best conductor, because it doesn't tarnish. I use silver-plated rotary switches.
But I'm not really an audiophile. I'm an engineer with some of the most cutting-edge analog products. I simply cannot see putting cables in liquid nitrogen, to align the crystalline structure in the metal conductors, because when the cables return to room temp., the crystalline structure reverts back to what it was initially.
The cables must be kept cold to maintain the effect. That means running a high-amperage compressor to liquefy the nitrogen. That's going to create inductance that will more than offset any gains from crystal alignment. Although I do sometimes dream of auditioning certain pieces of equipment I come across online.
I'll have a look at Please feel free to respond to my overly verbose rant.
Tom - E-mail: forensic (at)

Hi Tom,
you forgot to mention the most important of all audio components, snake oil...
The reason for which everyone sticks to RCA in my view is simply standardization: no one would buy any expensive audio component if there were problems in connecting it to the rest of the system. Standardization has both positive and negative effects: in case of audio, you can connect any components dating back to 1970 with any current one, but this also means that the connectors structure has not been improved in 50 years.

However, there are in facts subtle but audible changes depending on interconnect and speaker wires. Most of them cannot be accounted for with measurements, but can be heard without any doubt. Sometimes the changes are not subtle at all: years ago I spent a few hours trying to find out what was evidently wrong with a system, just to find out it was all due to the sophisticated speaker wires. Human hearing is a very complicate matter.

In other cases, however, the differences are only advertising hype. The only way to know, in facts, is listening in your own system, and even this is not always enough, as sometimes a component masks out the effects of another one.
Audio is definitely not snake oil... but sometimes very very complicated.
Giorgio Pozzoli

Question about playing 78's on ordinary 33/45 turntable
Hi David,
I have a quick question about playing 78's (and I suspect I know the answer).
I recently bought an "album" containing four 12" HMV 78rpm records (of a Beethoven string quartet). I have a record deck but it only has speeds of 33 and 45. Also it has a non-removable diamond stylus (I am using an MC cartridge).
I am wondering what would happen if I tried to play these records with my cartridge. Would it damage the stylus? Ideally I could (maybe) record the output and then look for a program to speed up the recording and/or remove the RIAA equalisation.
I am not too worried if I can't play the records. I bought the album as a curiosity. I can use it to explain to my friends the origin of the term "album" (although I am not old enough to have ever seem one before).
Best wishes,
James - E-mail: j.hamilton (at)

Hello, James,
Thanks for writing. I would hesitate to play the 78s with your moving coil cartridge's LP stylus for a couple of reasons. First, as you suspected, there's a good chance it could damage the stylus, which then would do bad things to LPs you play afterward. Second, even if the stylus is unharmed, it will give you truly awful reproduction. The grooves of standard 78s are much, much wider than LP grooves and hence take a bigger stylus; I've met the occasional one that can be played successfully with a 2.5 mil elliptical, but never one that worked with a 2.0 mil--and those are bigger than LP size. With an undersized stylus, not only will the groove walls not properly grip it to give clean reproduction, but you'll be riding on the very bottom of the groove, tracking through the detritus of ages.

So the short answer is, not recommended. Sorry about that--I wish I had better news for you. Maybe you could borrow a turntable with appropriate cartridge/stylus and copy the records? Or pick up an old Dual with 78 at a yard sale? I know getting another turntable just to play one set of 78s is a bit like tilting at windmills, but then, I did that once just to play one side that tracked too far into the center for my usual turntable, so you can say that 78 collectors do crazy stuff sometimes!
Anyhow, I hope this helps, if only negatively.
David Hoehl

Zero Zone IRS2092 Mono Amps
Hello Lucio,
I read your review and have treated myself to a pair of Zero Zones. They are all you say in your review. For me the sound staging and build quality are the most impressive features of these amps. I have been using them with a Soncos Dac using the pre section it is fitted with. I tried an active pre but found the Soncoz a better match. This set up can put a bomb under my PMC floorstanders. I found the sound quality to be excellent.
Have a look at Their UDP 320 True digital power amp at £90+ is an interesting product I own. A power 48v power supply is needed and I have built one using his 48v board. A Meanwell GST208A ready built supply can be used which they can supply. They also have a ready built dac with the top Sabre Pro chip set and a 150w class D amp which can use the 48v supply.
Michael - E-mail: michael665booth (at)

Dear Michael,
thanks for the feedback on these impressive monoblocks. They astonish me day after day. And we're receiving extremely positive feedback (like yours) from readers who have purchased the ZeroZone's after our review. Let me thank you, as well, for the useful suggestions on other power amps and DACs, as we're always searching for outstanding quality/price ratio HiFi components like these!
Thanks for the feedback,
Lucio Cadeddu

Yamaha A320 2019 review
Hello, just read you report on the Yamaha A320 and was impressed by the comments you made. I have one of these old birds for 35 years now and its getting a bit long in the tooth but sounds great except for loosing sound in the right channel occasionally when I turn the volume or if I change the course, which all goes through the smart TV except for the CD.
You mention deoxidising spray, perhaps this can assist here, so where do I spray this and as I live in Sao Paulo and could be a language interpretation issue, what is the chemical components of this as I need to be clear that if I buy something I am not getting something that will destroy the amp.
Can you be a little more specific where to spray on the images in the report, I am not familiar with the terminology of the components.
Thanks again for your interesting article.
Christopher - E-mail: cjamessimmons (at)

Dear Christopher,
glad to know you enjoyed my review of the Yamaha A320, a little vintage gem. Any grocery/DIY store might supply what you need, just ask for an electrical contact deoxidizer spray (CAIG, CRC, whatever). Then spray on contacts/switches/selectors (inside the amp) and into the volume control/potentiometer as well. Be sure to disconnect the amp from the mains before performing this procedure. Also, let the spray dry a little bit before turning on the amp. In the meanwhile, rotate the volume (fully up and down) several times and operate the switches on and off several times as well. This mechanical action, together with the deoxidizing spray, should destroy any trace of oxidation. If you're not familiar with electronic components, have a friend doing this for you. It's better to be safe than sorry. Moreover, any TV/radio service can do this operation on your behalf for few $, it is pretty common practice. In any case, this video tutorial explains the procedure quite well :-)

Hope this helped somehow,
Lucio Cadeddu

Connections oxidation
Just read your review on the rebuilt of a pair of AR94 loudspeakers. You are wise in your approach to connections, most people don't seem to know, even in the audiophile world, that most metal oxides act as a rectifier or diode and can really mess the sound up in a hearable way. Copper oxide is a particularly good rectifier, was preferred for some applications prior to semiconductors. All connections are bad without doubt, anything relying on pressure that does not create a cold weld is guaranteed to impact you sooner or later, I sometimes wonder if the people who swear by monster cables etc really did not just have a bad connection and renewed it when they swapped out the cables.
Gareth - E-mail: gareth.smith (at)

Dear Gareth,
thanks for your feedback! Yes, contact oxidation is a problem, for this reason many connectors are gold plated, because gold doesn't oxidize easily. That said, gold is a worse conductor, when compared to copper and silver. Some high-end manufacturers use rodhium, instead of copper- or gold-plating. Rhodium metal does not normally form an oxide, even when heated. Its high cost, though, ensures that rhodium is applied only as an electroplate, actually. It is valued for having small electrical resistance, small and stable contact resistance, and great corrosion resistance.
In any case, if concerned with oxidation, just clean the contacts often, using a good contact cleaner for electrical use, or just plug/unplug the connectors several times. This simple mechanical action helps fighting oxidation.
Hope this helped somehow,
Lucio Cadeddu

Jolida JD9
Hi TNT. Just got through reading your review of the Jolida JD9. May I ask a couple questions, please? Obviously this handles mm and mc cartridges. Are there variable settings for the MC cartridges or is it one setting and hope it works for your cartridge? For a low output MC cartridge, is there enough gain available?
On another topic, sort of, I am wrestling with the question of getting a solid state pre that has all the adjustments for different MC cartridges and running in through a tube amp. What has been your best experience?
Sorry for all the question by having collected solid state gear for 45 years, the tube bug is interesting me, especially the Chi equipment, For an amp, I don't need more than a 20wpc amp, but whether to use a solid state pre and a tube amp or both pieces tube. I like the mellow tone I have heard from tube pre's.
Any suggestions would be greatly appreciated.
Keith - E-mail: keithbohm (at)

Dear Keith,
yes, the JD 9 offers many different settings:

This means it can easily interface almost any MM/MC cartridge on the market! As for your choice between a tube or a solid state preamp, it mainly depends on your system configuration. If you just use the turntable, you can decide for a tube phono preamp like the JD 9 and then use an integrated amp (even solid state!) to drive your loudspeakers. But if you use different sources and you wish the tubey sound on all inputs, it should be better to choose a solid state phono preamp (say, a Lehmann Black Cube SE, which has different settings, as well) and then decide for a tube integrated amplifier. This way all the sources will benefit from the same sonic imprinting. Of course you can go tubey all around, with a tube phono preamp AND a tube integrated amp. If you don't need much power, an integrated tube amp won't cost you a fortune. The proof is in the pudding, of course, so try to listen to some different configurations whenever is possible.
Hope this helped somehow,
Lucio Cadeddu

Re: Your Topping PA3 review
Hi Lucio,
Just spotted your response, re the lack of bluetooth and remote control on the Topping PA3.
The PA3 is being marketed, probably correctly, as a power amp. The majority of power amps are black boxes. There are virtually no controls, there are inputs, in many cases only one, and there are outputs, again, in many cases only one. Control is undertaken at the preamp stage, in my case this is performed by a Topping DX3 Pro. The Topping DX3 Pro has only preamp and headphone output. I therefore find myself in disagreement with you on these specific points.
On the point you made about DACs and specifically the sample rate, I agree, anything greater than Red Book can, in some cases, be dubious to say the least. Regards,
Adrian - E-mail: adriannavan (at)

Dear Adrian,
I'm well aware of the fact the guys at Topping think the PA3 is a power amplifier. The prefix PA probably stands for Power Amplifier, indeed. Despite of this claim, the PA3 is NOT a power amplifier. It has two line inputs, that can be easily selected, and a volume control. Hence it IS an integrated amplifier! This is the name which has always been given to such components during the last, say, 60 years. Moreover, using two volume controls in series is, generally, a no-no. Hence, if one wants to use the PA3 as a real power amp, its volume setting should be set to its max. Even better, its volume pot should be removed, as it is an extra unnecessary component along the signal path. That said, enjoy your Topping pair!
Thanks for the feedback!
Lucio Cadeddu

Your Topping PA3 review
Hi Lucio,
I enjoyed your review of the Topping PA3. I totally agree with the majority of the review having owned and run a PA3 for over a year now. The only point that surprised me was your mention of:

I have paired my PA3 up with the DX3 Pro DAC from Topping. Not only do the two pieces of equipment match aesthetically but the DX3 Pro handles bluetooth and has a simple but effective remote control. The two inputs on the PA3 are really useful because I also run a vintage Rotel RDP980 DAC which in my opinion beats the Topping DAC in almost every way but only copes with sample rates of 48kz and below. Hence running both DACs.
Adrian - E-mail: adriannavan (at)

Dear Adrian,
nowadays an amplifier which doesn't manage Bluetooth and doesn't have a remote for volume adjustment and sources switching is a nonsense, to me. The Topping MX3 has both, I believe it wouldn't be a giant effort to add these inexpensive features to the PA3 as well, even if that would make the selling price increase by some 10/20$ or so. It will make the PA3 much, much more desirable. That said, it's a marketing choice, and it's up to Topping to decide how to design their own components. I'm just a reviewer who can suggest some easy improvement, based on my experience on what audiophiles ask for.
As for the Rotel DAC vs the Topping DAC...forget the higher resolution thing, it is mostly a hoax. Connect the Rotel DAC and forget the rest.
Happy listening!
Lucio Cadeddu

Re: Fidele Audio upgrades on NAD amp
Hi Lucio,
Thank you for replying to my email on your website. I did indeed “break in” the amp with over 100 hours of continuous play but unfortunately there was little or no improvement. I also contacted Peter in Fidele Audio who said that he hadn't come across this issue before. However he did suggest that I send the amp back to him to have it checked out. As I'm based in Dublin and he in Scotland it would be expensive to do so. I have already payed for shipping there and back, including import duty courtesy of Brexit, when I had the upgrade done.
Peter also suggested that I change the RN60D metal film resistors that he used in the power amp back to carbon film resistors to see if that makes a difference. He kindly offered to send these over to me if I could find somebody to install them. Apparently some enthusiasts prefer carbon films, particularly in valve amps.
The use of the word “harshness” in my previous email was perhaps misleading when describing what I am hearing from the amp. The word “piercing or sharp” might be a better description as it is not distortion. For example brass instruments, guitar solos, higher registers on pianos & keyboards, snare drums and even vocals at times are piercing to the ear and sound too sharp causing discomfort after a short listening period. At a guess I would say that frequencies circ. 1kHz and above are the ones I'm referring to. It is like the balance is uneven between higher and lower frequencies in that the higher ones are louder then the lower ones. Rolling off the treble doesn't really help as that is set at around 10kHz.
I will have the metal film resistors swapped out for carbon films in the power amp section as suggested by Peter. If this doesn't solve the issue then I don't know what to do. If you have any further suggestions I would be glad to hear them?
I think it prudent that a listening test should always be carried out after an amplifier has been upgraded before returning it to the customer.
John - by e-mail

Dear John,
glad to hear Fidele Audio offered to check the amp again, this proves they are a serious and professional company. You can follow their advice on installing carbon resistors back, but I don't expect this will cure the problem. After your description, things are getting clearer. Sometimes we get used to a warmer sound, given by outdated/worn our caps and lower quality passive components. Many vintage components sound this way exactly for this reason. Fidele Audio brought your amp to “like new” specs, and that wasn't good for the equilibrum of your system. Moreover, higher quality passive components tend to sound more detailed and transparent, and this - in some sense - makes the mid-high range more pronounced. You can try to revert the amp to the original specs or try to sell it as is, a recapped/upgraded unit is highly desirable, in general.
Keep us updated!
Lucio Cadeddu

TNT FleXy with maple wood and steel
Dear TNT,
I've added some rope wires to your TNT FleXy DIY rack in order to minimize racking.
Gerardo - E-mail: soccerTOOLsu (at)

[Upgraded TNT FleXy rack]

Dear Gerardo,
thanks for your feedback and congrats for the smart idea of adding steel wires to make our DIY design stiffer. Nice job!
Happy DIYing!
Lucio Cadeddu

Lenco L75 tonearm repair?
Hi Roger,
And thanks for a nice article on tweaking the L75 and tonearm. As the proud owner of a drooping one, I wondered if anyone has tried sawing the offending bit off and sticking something inside to attach it to the rest? Not a wire but just a glued metal rod or something like that if it is even possible.
Giving mine a refurb and a new plinth and would like to fix the arm, but making a bit prettier than the outside rod or glue/tape.
Mikael - E-mail: MikaelSeierup (at)

Hi Mikael,
No doubt some people have tried to do as you suggest however I have never heard of anyone who has done that with success. I think that if one had access to a precision machine shop it would be possible to invent something to securely attach together the 2 pieces but, in my opinion it is not worth the effort. It would probably be easier just to make a new armwand!
If you invent a new solution TNT-Audio certainly would like to hear about it.
Roger McCuaig

Some Lenco tonearm advice needed
Hi Roger,
Thanks for your brilliant article on repairing the Lenco tonearm. I have a Goldring Lenco GL69 with its original tonearm with the square counterweight. The back is definitely drooping, would the same repair you did work on this tonearm? And I guess I'll need to find a way to get to the v blocks? They look quite old. I had thought about putting a linn basik straight tonearm in but that might mean losing the lift mechanism on the Lenco that's really great.
Any advice would be greatly appreciated.
Greetings from London UK.
Best wishes
Chris - E-mail: chrisredgrave (at)


Hi Chris,
I am very happy that you enjoyed my article. The internet is saturated with DIY Lenco stuff so I wasn't sure that another one would be appreciated! I have no experience with the GL69 however I looked at a few photos this morning and it appears to me that the armwand is the same and therefore you should be able to apply the same remedies that I outlined for the L75 arm. If you remove the counterweight and bend the counterweight shaft down a bit and you see a very thin steel wire holding the 2 rods together, then you can certainly conclude that it's the same as the L75. Beware, if you bend it too much, say 40 degrees, you could snap the wire! Have you been able to determine if your unit takes the same V-blocks as the L75/78? If not you might want to check that. No doubt it has been posted on the LencoHeaven web site.
I recently installed a rebuilt Linn Akito arm on my "Big Lenco" and it is performing exceptionally well. You should see a DIY article on this subject appear sometime soon on Here's something that you can do with your Linn Basik if you are interested in experimenting a bit. Leave the original Lenco cueing lever in place but remove the Lenco cueing arm. Just unscrew the height adjustment screw all the way out and the cueing arm will lift out from the top. You can then try the Basik without interference from the original cueing parts and easily go back to the Lenco arm by just screwing back in the removed Lenco part. Of course I have not addressed here the question of installing the Basik arm. One solution that I have used in the past for Jelco arms is the get an aluminum mounting sleeve (similar to the Lenco part) made in a local machine shop. It works perfectly.
Hope this helps.
Roger McCuaig

SS 3602 on Maverick D1
After reading your review about Sparkos Labs SS 3602 Dual Op Amp, I tried them on my Maverick D1. At first it was great, but soon something went wrong. Is it possible that the regulator of the maverick is too weak to handle them (there is only 2 on the D1).
Marcel - E-mail: marcelroyer.59 (at)

Dear Marcel,
sorry to hear something went wrong with this upgrade. Mike wrote in that review:

“The Maverick uses the cheap and functional 78XX and 79XX voltage regulators to supply the op amps. There are numerous options for better quality regulators so I asked Andrew from Sparkos if there was any benefit to upgrading the regulators. The response was interesting, as the Sparko's op amps are operating in class A, their demand on the supply is much more constant. With the regular op amps operating in class A/B mode, as the output voltage of the op amp increases so does the current demand and the supply must follow this. This means the regulators must have the ability to hold the voltage constant whilst at the same time deliver varying current at audio frequencies. Most regulators were not designed to meet these varying demands. I may explore voltage regulator upgrades for the Maverick in a future article.”
Perhaps that's the reason for the failure, the regulators on your D1 weren't up to the task. I'd contact Sparkos Labs to see if they can give any further hint or suggestion.
Keep us updated!
Lucio Cadeddu

Doge 7 DAC
Hi Roger,
I just re-read the review and I see now you meant that the unit sounded more transparent when you ran it directly into your power amp, thus bypassing a separate preamp. So, as I suspected, the tube output stage in the Doge is in play even when using the unit in the volume control mode. Sorry for the initial misinterpretation.
Brad - E-mail: bradwkap (at)

Hi again Brad,
Yes, you have got it right, I can run without a preamp and just use the tube analog output of the DAC. Regarding the digital volume control question that you mentionned in your previous email, I can give you a bit more detail on that topic. I understand that ESS has published some data on this however I was not able to find it this morning. The information that I am providing here comes from a third party source. I cannot say that this is 100% acurate however it appears to be reliable.
The digital volume control is done inside the DAC chip. When the Doge 7 is set to preamp mode, the ESS DAC chip applies a multiplier to all the digital data. This is done before the oversampling filter and results in a new digital value. The last bit produced this way must be rounded to 16 or 24 bits (and dither applied) and the remainder is lost. So the least significant bit of the data has a quantization error. For a 16 bit signal we are looking at a difference at -96 dB (barely audible) and for a 24 bit word we are at -144 dB which is way below the noise floor of any gear!
Hope this helps.
Roger McCuaig

Lenco L75 Corian Platters
Hi Roger, Thanks for the review on this Lencohell upgrade. I'm also in Canada in the GTA area myself. I'm also in the process of building my 4 Lencos. Have you used the CLD plinth design as I've previously done and has since been sold. I would love to compare notes. I'm in the process of ordering the SPH bearing and possibly his PTP style chsssis.
Steve - E-mail: scoconis (at)

Hi Steve,
Yes, I have rebuilt several Lencos over the past 10 years using a CLD style plinth. There are very many variations on the CLD plinth of course. In my case I have pretty much stuck to the basic design that Jean Nantais published 20 years ago. I know, as I have just reviewed Jean's recent model, that the TJN Lencos have evolved quite a bit from his original CLD plinth. He is now using some special woods (he won't tell me what they are) and has modified the outside layers. I have never used the SPH bearing however I think that I may eventually buy one. I use the original Lenco bearing design in my Lenco rebuilds however I install new sleeves and a new ball, all available from your local bearing store.
I buy mine at General Bearing. I also replace the original Nylatron thrust pad, which was never designed to last 40 years, with a slightly thicker Acetron pad. It has less friction and is also very much harder to dimple that the Acetron pad. With respect to the PTP chassis, I have been contemplating contacting Peter Reinders for a review sample. That would mean building another turntable from scratch though!
If you want to "compare notes" that's fine. Keep in touch.
Roger McCuaig

Thanks for your Topping reviews!
Thanks for reviewing the Topping PA3 and MX3, based on your informative and nicely written reviews, I decided to go with the PA3 as an amplifier for on my desk in my office. Will be using a pair of Dali Spektor 1 speakers.
Greetings from the Netherlands,
Martijn - E-mail: martijn.estor (at)

Dear Martijn
I'm glad you enjoyed my reviews, those amps are pure bargains, indeed. The PA3 will have no trouble at all driving your Dali Spektor 1 loudspeakers. Just keep us updated about your findings!
Happy listening!
Lucio Cadeddu

Audio Note Io1 review
Hi Graeme,
Nice review, sir. I have used one of these on numerous occasions and can 100% concur with you findings. Forgive me but can I assume the photos were taken before the cartridge was aligned? I ask as in the instructions for the arm/cartridge, the front of the head shell perfectly dissects the front head shell hole when correctly aligned and I tested this to be correct. I assume you'll be holding on to it too, if so, good choice. I can also inform that my Tom Evans Groove+SRX, MC only phonostage, set up for my Dynavector DRT-XV-1t has more than enough gain and ridiculous low noise floor to use this beauty. What ever you do don't audition the Gold!!!
Simon - E-mail: simonpcwalker (at)

Hi Simon,
Thanks for writing - glad you enjoyed the review. As for alignment according to my Polaris Plus protractor the alignment is correct in the photo! I checked again this evening and it's spot on on that position! May I ask which arm/TT combo you tried with the Io 1. I didn't get instructions so I relied on the protractor even though it looks a bit weird!
Thanks also for the phono stage info. Always good to know!
Kind regards,
Graeme Budd

Fidele Audio upgrades on NAD amp
Hi TNT, I've just finished reading your article on regarding the Fidele Audio upgrade to your NAD 3120 back in 2006. I bought a NAD 304 in 1995. This model is very similar to the 3020 in that the preamp and phono (MM only) stage are almost identical. The main difference being the power supply and power amp are a more modern design which includes some complex protection circuitry. A few months ago I decided to have the amp upgraded so I went online to find someone that could do this for me. That's when I came across Fidele Audio. I emailed Peter Hickman and he was happy to do the work. The upgrade was similar to your own which also included swapping out the caps for audio grade Nichicons and upgrading the resistors in the signal path to Vishay metal film type.
When the amp was returned to me I hooked it up to my NAD 514 CD player and NAD 804 speakers which was the system I'd been using since I bought the amp. I put a CD in the tray and hit the play button. To my dismay there wasn't a big improvement in sound quality overall. What there was however was a harshness to the high mids and treble frequencies that wasn't there prior to the upgrade. So much so that listening fatigue set in after a short period and I had to turn the amp off. The CD player and speakers were always a bit lively but no where near as harsh as this.
Did you notice an increase in this frequency range or something similar to my experience with your own upgrade?
John - by e-mail

Dear John,
sad to hear about your disappointing NAD 304 upgrade! No, it is not normal at all, it should sound clearly better, not worse! The first thing to do would be to contact Fidele Audio and ask for some explaination. Secondly, I'd let the new components “break-in” for a while and see if something changes for the better. New, better components might add some extra liveliness to the mid/high range, but certainly not harshness! Consider that old passive components like caps and resistors tend to sound warmer, simply because they've lost the original electrical parameters and, hence, performance. This is way many audiophiles seem to prefer the odd warm and mellow sound of vintage components: simply, they do not sound like when they were new! The sound tends to slow down and becomes warmer.
Keep me updated, I'm curious!
Lucio Cadeddu

AudioEngine A1 speakers
I've used the AE2 for several years now, connected to my iMac basically for background music. They are great speakers, even when you turn up the volume. I did try using my CD (Accuphase) and later incl my pre (Air Tight) and it makes a very impressive sound.
I think the changed from Class AB to D could be due to the heat as there is no external heat sink. My left speaker was affected my this. The mid/woofer cone deteriorated and crumbled! I have since replaced the mid/woofer cones with what I could get on the internet. Unfortunately they are not matched pairs (but they were cheap), so one much louder than the other. Sound better than my KEF Muo.
Just thought give some feedback as a user. Yes, I would still recommend them to anyone looking for a pair of small speaker.
Teng - E-mail: ongtb6 (at)

Thanks for the insights! I think both models are terrific values for the money, and I'm glad to hear someone out in the "real world" confirming my opinion that they are good performers, although I'm sorry to hear of your mishap with the one cone.
Happy listening to you!
David Hoehl

Bright Star Audio Isonode
Hi Mark,
I read your excellent review of Bright Star Audio's Isonode vibration absorbers and would like your opinion of which would be best for the following equipment?

  1. Yamaha 801 Integrated Amp - 26.2 lbs
  2. Cambridge Audio CXC - 10 lbs
  3. Ifi PowerStation 5 - 10 lbs
Kindly let me know?
Edward - E-mail: ejfroe (at)

Hi Edward
Thank you for your kind words about my articles. I am aware that they were written many years ago, but the findings still apply. I am guessing that you refer to the Bright Star Isonodes and that "Isonets" is the product of an enthusiastic spellchecker. Since then I have tried several similar alternatives from various sources and the Isonodes and the Bright Star Isonodes remain the best of the bunch and excellent value. They certainly win over fancy wire as a measurable and tangible and effective means of improving audio system performance.

As you have implied in your query, the weight of the component is the principle distinction between the choice of small or large Isonode. As you know, with hard feet I recommend three supports, but with soft feet any number is possible. I have found with Bright Star Isonodes (which I still use constantly) it is best first to establish three factors about each component:

  1. The mass of the component
  2. The centre of gravity of the component
  3. The parts of the component chassis most prone to vibration
  4. The ventilation holes

The small Isonodes can support up to 30 lbs max per set of four (I assume that you are writing from a non-metric location and Bright Star also live in the land of avoirdupois). Distribute these equally around the C of G at the most vibration prone areas. The large Isonodes can support up to 42lbs and I would choose these for your amplifier because it will enable you to place an inert mass (Victorian quarry tiles are effective and Barry Kohan can also sell you the Little Rock ballast) on top of four more small Isonodes on top of the amplifier for greater effect (the top plate is usually even more resonant than the chassis base).
I hope this is helpful.
Happy tweeking,
Mark, The Old Scribe

Trenner & Friedl SUN
Hi there,
I just read through the your review on Trenner & Friedl SUN speaker and really thanks for sharing your experience. Actually I could see for this speaker, the sensitivity is quite low. Thus how do you make sure it is driven properly? What amplifier did you use to drive it? I could see from somewhere that people drive Trenner & Friedl speakers with Jeff Rowland amp but I am not quite a fan of D-class amp. Want to know your opinion.
Eddie - E-mail: qijinpeng19 (at)

Dear Eddie,
yes, the sensitivity is very low, but this just implies you should use some extra watt to get your desired sound pressure level. There's no reason to use a particular technology (Class A/B/D/whatever) provided the amplifier can deliver good watts. And there's a limit to power handling, as well, do not forget the size of the drivers. As remarked in the review, you need good watts but you shouldn't exceed the natural limits of the drivers. How many watts? Well, that mainly depends on your listening habits and on the size of your listening room. As said, I believe that at least 30 good watts per channel are mandatory. Remember: quality is the keyword here, not power.
Happy listening!
Lucio Cadeddu

Aluminum cap for Denon DL-103
Hi Roger,
I've just read your 2018 review of the DL-103 with the aluminium cap.
It's been a while since I last used a stock 103, but I've used (and abused) at least 3 or 4 of them throughout the time. At some point, I removed the plastic body, which helped reduce some of the "plasticy" sound character, later I trued filing off a tiny bit of excess aluminium on the tip of the cantilever, which provided some needed treble and air.
I've also experimented quite a lot with decoupling the cart from the headshell, using different materials in order to reduce the amount of vibrations to move back up into the headshell and arm. All of these experiments provided audible improvements in my arm, which by that time was a primitive Fidelity Research FR-54.
Later, I've purchased a 103R, quite a lot better than the standard 103 if you ask me, and a better bargain too, even at the higher price. But with all my former experiments in mind. I used the decoupling and the filing the tip of the cantilever tweaks on this cart as well, and with splendid results. As I write this, the 103R is mounted in a mahogany body on an Audiomods Series VI arm. The plastic body of the cart has been removed entirely.
The decoupling was achieved by adding a VERY thin layer of bathroom silicone to the bottom of the mounting plate, and then screwing the mahogany body tightly to the mounting plate. The cart itself is glued inside the mahogany body, no screws here. I did have to operate on the mahogany body in order to use my available screws, but this won't be necessary for everyone; it simply depends on which screw lengths you have available.
The sound quality of this all put together is way beyond what I have ever dreamed of, and equally above any 103R I've ever heard before or since. The amazing silence of the extremely well damped arm sure plays a large part of the resulting sound quality, admitted, but having further reduced the vibrations of this rigid cart from wandering up the chain, certainly helped as well. I feel these tweaks should be tried out at TNT, either with a standard 103 or with a 103R, or both. It's worth it, I promise. But the 103 family seem to prefer extremely well damped arms in my opinion, so mounting it in a half decent SME arm won't cut it. Metal tubes is not the favorite arms for a 103 IMO.
In case you'd like to copy this to your website in order to share it with your readers, you are most welcome, and if you have questions about anything, I will do my best to provide any and all details about these tweak procedures.
Keld - E-mail: saintkelo (at)

[Audiomods Denon DL103]

Hi Keld,
Thank you for your interesting email!
Enjoy your music,
Roger McCuaig

Linn Index mk1 loudspeakers
Hi, I recently purchased a pair of Linn Index mk1 speakers. Initially I drove them with AIWA 8100 amp: very boxy, thin sound. I had just purchased a mint 8100A AUDIOLAB AMP. I wired the Audiolab to the Index...what a beautifully balanced top end and to me a nice moderate bass. I think these are the true LINN SOUND as they were the first Linn produced. To me 100 eur very well spent!
Regards my friend, let me know if you do a piece on this.
Tony - E-mail: tonymcdonagh635 (at)

Dear Tony,
I reviewed the second version of these babies, the Index Plus, no plans to review a first series model, which is also extremely hard to find, especially if you don't live in the UK. As far as I know, the Plus's were definitely better sounding, but it seems even the first series can be extremely satisfying. Place them very close to the rear wall if you need more bass output, as they were designed to be placed this way. Your 100€ have been well spent, that's for sure!
And, please, do not use Aiwa amplifiers anymore! :-)
Happy listening!
Lucio Cadeddu

Sure TA2024
Dear TNT,
I am writing for an advice on the small Sure 2024 amp. I have a pair of Acuhorn 125's, used with various (even expensive) class D amps, all inflating the mid-bass. I jokingly tried a TPA3116 which wasn't too bad considering the cost. Reading various things I read that the 2024 was more refined in the upper midrange, or simply with less bass it brings out the top end better...
Well it was true, I stuck this little amp in my full range amps and it seemed to work very well (at least in my room). My question is: Does it make sense to use it as a power amp since it has volume?
Maybe I should get a Trends Audio TA-10.2P?
Best Regards,
Riccardo - E-mail: baruzziriccardo (at)

Dear Riccardo,
of course you can use the Sure TA2024 with its volume set at its max. On the other hand, using two potentiometers isn't a good idea, even if it works. I'd prefer to use a TA2024 without volume control. Either you remove it from your Sure TA2024 or you purchase a (better sounding) Trends TA10.2 P.
Happy listening!
Lucio Cadeddu

Caveat Emptor article
Dear Roger,
in response to your last article on the caveat emptor mantra, I'd like suggest a different perspective.
First, you should have considered the main factor in commercial experience like yours: geolocation.
I can only speak for my little provincial, empire's borders experience, here in Naples, Italy.
I'm old enough to have passed through the roaring eighties (here, they were particularly “roaring...”), the shimmering nineties, and so on... I missed the seventies, but I suspect that, while a wonderful period of blooming companies, product, ideas, and so on, it is also a period tendentially over-praised by the people that “were there and made it through”.
Well, I still remember a shop in the city's most elegant shopping district, that sold furniture at street level, but in its windows showed off all high-end (they were not bearing such a label, then...) audio goodies, that were sold in the huge basement level. I still remember hangin' out there after school on the way back home, or in some homework-free afternoon, listening to wonderful gear; the systems often playing for “real”, paying customers (there has been a time when there were some of those, rest assured :-)), but also sometimes switched on just for “us kids” (contrary to the common sense, in places like that one, nerds are never alone...).
I NEVER was one of their customers, and they knew it well, since they “weighted” me and my “economical force” as soon as I walked in. But I was polite, always clearly “exploring” and never asking attention for myself; so, they didn't bother having me there, actually even inviting me to audition something new or an unusual setup. I'm sure that in their commercial dealings they sought - and got - a robust profit, but I can't recall a hearsay of bad reputation: they asked steep prices, but that was according to the gear they were selling (and the customers they dealt with), and they gave an after-purchase service, albeit minimal (setting up the system in the buyer's home, coming to that places in case of faults, even just for taking the faulty component and send it to the - very few - repair services, and so on...).
This all could be possible in such a small environment, like the one where we all lived, buyers and sellers. That kind of “commerce” couldn't be thought of without the personal contact between the parts, and the immediate - “social”, we'd say now - resonance that a bad move from either part would have had. That's quite different, I think, from US o Canadian experience, where the retailer's clients come from everywhere, from many miles away, eventually seeing each other just a couple of times in their lifetime. It seems only a one-to-one affair...
Second, you are suggesting that the retailer is there mainly to see you as a spring of (part of the) money flow he needs to get along with the business. He is NOT there to be you FRIEND. Well, that's another point that I think is strictly connected with the “geolocation” I was talking before.
Since high school, I ended up visiting mainly another store (the previous one suffered a forced change in location and the market was getting more into the snobbish high-end area; both things sent me away from them). This second store was managed by a well known high-end artisanal producer and, mainly, by its son, who is slightly older than me. I' not meaning we've become FRIENDS, but I can assure you that he had and still has an attitude towards all his “clients” more like a bartender than a retailer. He not always “tolerates” us hangin' out there, but often urged us to do so. We “used” its place also as a “hub” for the “audiophile community”, passing by also (mostly) when we didn't need to buy anything, just to “listen to what's new”; and now it is one of the few places where important brands show off (until it was permitted...) their news.
Sure, in his business operation he seeks his profit, but I still don't recall any hearsay about mistreated customers. Unfortunately, our market shrank, because so many of us lost almost all their buying potential, eroded by the shortage in work and payments and the rise of life's costs. So, there's a big resurgence of the second-hand market, and this tends to be - I guess - his main “cashflow” source. In selling used gear, he, as a salesman, surely is charging more that the buyer could spend buying directly from the former owner, and surely part of its “selling weapons” is the audiophile reputation of the used gear he is selling, thus unavoidably depending on (and endorsing) the snake oil that things come with; but he is anyway still letting used gear move, since he provides that sort of aftermarket light assistance I described before (even home auditions...), plus he still tends to be the “center” of our little audio circle. It is always not only a commercial experience, not only a buy/sell meeting of wills. I think his attitude couldn't have followed this path, were we placed in an area where clients are spread over long distances, just like seems to be there, “over the pond”.
Here's a recent article on the Sound and Vision Website. There, I seem to read a similar view, especially in the comment section: clients accustomed to travel a long way to interface with the retailer only, well, for the sale.
In conclusion, I'm just suggesting that the picture you are describing isn't always so dark. And that in many places - especially where people are used NOT to have much money in their pockets - the “caveat emptor” function is always on (hence, our now radical mistrust of EVERY politician and our pathological difficulty to undergo the exercise of public powers; but that's another story...).
I think that, more than that sane distrust (a pretty good rendering from the Latin origin of this word), maybe the real safety belt for the purchaser can be a community; acting as a soloist is usually never as good as playing in a group :-)
Then, if you want to sink in the swamps of the fictious pseudoscience that the marketing guys place their products in, you are free to do it, provided you're with someone who can help you in the decision. And if four eyes see the same things that two do, so be it, enjoy what you got and start listen to some music :-)
Thank you for having followed my ramblings until their ends.
Carlo - E-mail: md1809 (at)

Hi Carlo,
Thanks very much for sending us your different perspective on this subject. Always good to read about other peoples experiences.
Enjoy the music,
Roger McCuaig

Yamaha A320 review
Good evening Lucio,
I've read your nice review regarding the A320. Have you already recapped it? Do you have a schematic or service manual? I'd like to tweak my 320 and more insights about this amp are welcome.
Thanks in advance,
Kind regards,
Bram - E-mail: rheingold (at)

[Yamaha A320 - vintage audiophile amplifier]

Dear Bram,
glad to know you enjoyed reading my review of the A320. It's a little gem, indeed, and mostly unknown. And no, I haven't recapped it yet, it sounds very good even “as is”. In any case, it has found its place on my vintage collection shelves, I'll leave it there and use it for some comparison from time to time. I don't have a schematic or a service manual, unfortunately, but it is a very simple amplifier, anyone can look at it and understand its secrets. Moreover, you don't need a schematic or a service manual to recap it, just remove the old caps and solder the new ones. You can replace other passive components here and there, just to be sure. Just keep me updated on your project...
Happy tweaking and listening!
Lucio Cadeddu

Loudspeaker damping
Hi Mark,
after reading your 3 part series on regarding loudspeaker damping, I was hoping I could get your help. I'm building my first DIY speaker. I attached the design notes and cabinet plans. These come with pre-built cabinets just like the plans, no internal bracing. They only come with acousta-stuff for loose fill and this simple foam to line the walls:

How would you recommend to dampen these? For example, I can add dowels to cross brace. I'm also intrigued by this product. I want to retain the liveliness through the midrange. I don't mind a bit of bass warmth from the MDF's natural 250Hz and 500Hz resonance frequencies if it keeps the midrange pure and lively.
Another option is to substitute this for the foam for the interior walls:
Greg - E-mail: johnson.greg924 (at)

Hi Greg,
Thanks for giving damping material such consideration and for considering my article an authority on the subject.

I'm guessing that the 3/4 inch mdf cabinet come ready routed for the drivers. Therefore there is little mdf supporting that woofer rim, especially close to the tweeter recess. Any cabinet front (known as the baffle) movement (vibration) at this point, caused as a reaction to the bass cone mass movement, Will have a disproportionate effect on the tiny treble signal from the tweeter. This causes intermodulation distortion, a non-linear distortion which is one of the most unpleasant artefacts in audio.

Hence, task Number 1 is to stiffen that baffle with braces at that point. As you have used imperial measurements I will stick with those. Any offcut of dense hardwood (balsa is a hardwood and far from dense, so that was no tautology) like oak, beech or one of the denser maples will suffice. 1/2" X 1/2" square section is enough in this location from the cabinet top down to the top of the bass=mid unit and from just above the slot vent diagonally in toward the bass-mid aperture.

As you suggest, hardwood dowels across the cabinet void will also help and will provide support to the stuffing. Sound absorbing layers on the walls help reduce reflections back at the bass-mid driver (paper coned in this instance) up to the frequency 1/4 wavelength equivalent to the thickness of the absorbing material. The Madisound foam sheet you link is 5/8" which in SI is 0.016m from 5kHz upwards which is therefore not useful on the cabinet sides.

Acry-Tech Acoust-X Paintable Damping Material is a different proposition. It's surface texture will scatter reflections and its composition will convert some energy into heat and its mass will lower the Q and the frequency of cabinet wall vibration. I suggest a both-and approach.

Centrally supported sound absorbing material (Acoustistuff, long-fibre wool, acoustic foam) best absorbs standing waves in the cabinet. A roll of the Madisound foam sheet will also achieve this, thus avoiding acoustistuff sag. Hence a front-back dowel close to that critical baffles weakness around the tweeter and bass unit apertures is a good idea piercing a roll of the Madisound foam.. Two dowels between the sides will help equally with strong 2 pack adhesive in every case (Aerolite 606 or similar measures better than pva in this context). The roll can be between the top side-to-side dowel and the front baffle and between the bottom side-to-side dowel and the rear. A further layer of foam on the bottom face of the loudspeaker exactly below the driver will reduce an early reflection there, especially if sculpted away from the driver. Having said that, do not overdo the damping or the port alignment will change and be ineffective. I note that Seas suggest playing with damping in the port according to loudspeaker location. The true function of a loudspeaker port is not some kind of magic to conjure bass where there was none before (ye canna change the laws of physics captain) but to control the bass driver/cabinet air volume resonant peak (hence the classic reflex double impedance peak) so damp the cabinet not the port air flow.

Seas make some excellent drivers, many of which I've used over the years. The kit you have chosen is based on an OEM complete loudspeaker system that they made that was badged Dynaco A25. It dates back to the audo heyday of the Summer of Love in 1969. They shifted over a million pairs so listeners must have loved them. Fabric dome tweeters tend to sound less like a series of resonances than plastic domes to the Old Scribe ears. Paper cones tend to sound faster and livelier than the heavy bextrene cones of the classic British sound of the same period, at the expense of a little midrange colouration.

On the other hand, mdf is the most life sapping loudspeaker cabinet material ever devised by humankind. Resonances subtract (known appropriately as destructive resonances) as well as add. Bracing is therefore strongly recommended. Even better is adding a layer of 1/4" hardwood sheet instead of veneer to the outside of the sides, top, bottom and back of the cabinet instead of veneer. You could do this later so that you can hear the difference, or do it now and get it over with! As long as you round the corners of the 1/4" hardwood sheet there will be no effect on the baffle step frequency. The most available and cost-effective material I have found for this is sold as kits to rejuvenate wood flooring.

Another future-proofing idea is to connect the drive units to two sets of terminals on the rear of the cabinet. Mount the crossover on the outside so that it is not affected by the hostile vibrations in the cabinet. Later you might choose to experiment with a higher spec tweeter capacitor or even with active drive and this makes that easy.

I would anticipate that these loudspeakers will give you hours of fun making them and even more hours enjoying them. You also get the delight of saying "I made them!"

Do please keep me updated with your project progress.

Happy building and listening,
Mark Wheeler

Lenco 75 platter ringing
I just read an article on TNT and not sure what exactly was done to the platter. The picture is too small...I applied same stuff as you underneath - around inner thin (deep) rim but after placing it back on a spindle platter doesnt move :)
Where is the catch?
Thank you
Arunas - E-mail: uksminas (at)

Howdie to you too,
the most probable cause for your problem would be that the platter is rubbing on the platter brake. This is more likely to happen with an L78 due to the design of the brake however it could still happen on an L75. Especially if the material that you applied is thicker than about 2.5 mm. On an L78 the rubber brake pad can be filed or sanded down a bit to accomodate the added insulation. On an L75 it is a bit more difficult. You can try bending the brake lever which is made of a springy metal or cutting off the end to shorten it by 1 or 2 mm.
If you are having trouble viewing the photos on the web page correctly I suggest that you try changing web browser. Sometimes that has worked for me.
Enjoy your music,
Roger McCuaig

Love your site
Greetings from Jasper,
I just purchased some vintage audio kit. I am a MacHead and a collector of vintage devices. I am always enriched by the discovery of the knowledge base provided by a site such as yours. I am curious to know if there is a monthly newsletter I might subscribe to?
I have book marked your page and will be a regular visitor.
Thanks again!
Dave - E-mail: betabake (at)

Dear Dave,
we don't publish a monthly newsletter, as we update our website every weekend, with new reviews and articles! You can bookmark the What's New page and visit it regularly on weekends. You can even stay in touch with our updates via our official Facebok Page.
Glad to hear you love vintage gear! We do love good vintage components as well. Unfortunately, nowadays, everything from the Seventies and the Eighties is now considered vintage, even if it was bad sounding back in its days! From time to time we publish reviews of vintage components we love and, moreover, we have an entire section of the website, titled “On an Overgrown Pathé”, devoted to REALLY old components of the pre-LP era.
Hope this helps,
Lucio Cadeddu

Decca tonearm
Hello sirs,
searching informations on a vintage Decca original tonearm, I saw you review dating from 2008....and I thought you could maybe help me: having bought few months ago a wonderful Decca MKII stereo cartridge, I purchased just after an original Decca Tonearm.
But I don't have the "plan" to install it properly on the turnable ( a Garrard 401 )...! (it was not included with the arm). Would you know where to find the right one, very precise?
Just in case.....thanks in advance,
All the best,
J-M - E-mail: jmharari (at)

Dear J-M,
the instruction for proper tonearm installation heavily depend on the turntable where you will install it! In any case, assuming you have purchased the same tonearm I have (New in Box! A London International) these are the two pages of installation from the original manual...

[Decca tonearm installation instructions]
[Decca tonearm installation instructions]
Hope this helps,
Lucio Cadeddu

Headphones choice
Dear Arvind,
I'm Pierluigi and I've been a TNT-Audio reader for many many years. I've recently enjoyed your article about the AK OB1 DIY loudspeaker project. I found very very interesting technical aspects in it especially the open baffle design (and the fact that is diy). Great project but my question is not about the AK OB1, or maybe a quest that can be related: the AKG K 701 in your referenge gear: I was watching that headphones for some time now and I'm curious to ask an opinion to someone that have listen to them for some time, what are the strengths and the weaknesses or why that headphones are appealing to you? One of my thoughts is that being open back maybe the sound character is comparable to the naturalness of the open baffle speakers? Speaking of headphones actually my gear is: Sennheiser HD 600 for open back (21 years old now), ESS 422H for closed back, Fiio X5 gen. 3 as source (and dac) and a Fiio A5 as amplifier, I think that the HD 600 is a bit old because it starts to lack something, I remember another sound from it (or maybe I'm wrong) and I'm searching for a substitute. TNT-Audio to me is the most reliable source of information because it's not affiliated to any brand, the opinions are genuine and the authors are passionate people about hi-fi, so here I am. Please give your honest opinion about the K701, I will consider it as pure gold because for now I got only biased reviews but not a truly honest one. If it doesn't disturb you I would like to thank you for your precious time even if only for reading my words and I hope to have an answer.
Thank you very much and greetings from Italy.
Pierluigi - E-mail: wigi__ (at)

Hi, Pierluigi,
Thanks for your kind words, and glad you enjoyed the articles. See these comparison I had done a while back; see here. Subsequently, I picked up a pair of the 701s and directly compared to the Sennheiser HD650, and much preferred the AKG. Additionally, I have since acquired a pair of the Stax SR-44, and prefer the AKG's again. For as good as the AKG's are and as little as I use headphones, I have not had any more curiosity since I picked up the 701's. If I had, I'd also check out many of the newer electrostatic models.
I hope this helps.
Arvind Kohli

Digital Audio
I read the review of the DAC and I feel a headache coming on...why? The hum problem. Like you...I abandoned digital in 2007 to concentrate on Analog. Fast forward to 2021, I love analog and own the following:

Currently using a passive preamp which works really well just curious about trying the Doge 8. I will eventually get the Doge 7 D/A. I am thinking of getting back to digital. The reason why I got out of digital, I cannot get into the music with digital. I play digital for awhile but then switch back to analog and relax. I hope after a hiatus of more than 10+ years out of the digital has improved. I assume there is no way digital can sound as good as analog even in the higher sampling I wrong?
Ren - E-mail: renantebarroga (at)

Well I see that you have lots of toys to play with!
You are asking yourself THE question; can digital sound as good as analog? Today, you have put the question to me,I feel the weight of the world on my shoulders .....As is the case with many of us, I have been asking myself that question too.
I believe that digital music does not sound the same as analog, and probably never will. That doesn't necessarily make one of the other better, it just makes them different. I personally prefer analog for several reasons; it is what I grew up with, I love the look and feel of the record and to experience the artwork, and of course the special listening experience of vinyl playback.
My experience, as well as some of my audiophile friends, has been that over the past few years digital playback quality has improved immensely. I believe that it is for the most part due to improvements in DAC chips. I recently had the opportunity to review a new unit that has two of the latest ESS DAC chips in it and I found it very impressive. (review to be published soon) But a good DAC chip is just the start, a digital playback device has to be designed with the same attention to detail and component quality as is given to high-end analog equipment and that means not just the DAC chip but also the analog section, the power supply, everything.
In conclusion, I would say that there are digital music components available today that can deliver anything and everything that a top quality vinyl playback system can deliver with not a trace of "digital fatigue". Some days I listen to digital music all day long played from my music server PC running JPLAY FEMTO into my Doge 7 tube DAC, but it doesn't sound the same. Nothing sounds the same as vinyl.
One cannot speak on this subject without mentionning the significant problem of digital music compression, AKA The Loudness War! Great playback equipment can't correct some of the terrible things being done in the recording studios.
So, there you have my take on the subject. Hope you get something of use out of it!
Enjoy the music,
Roger McCuaig

Dodge 8 preamp review
I liked the review of the preamp...any chance you will cover the dac? I live in Montreal and I am assuming you like in Ontario, I was wondering how your experience with ordering the Dodge 8 preamp directly from Doge. Aamy problems or concerns?
Ren - E-mail: renantebarroga (at)

[Doge 7 front view]

Hi Ren,
Nice to hear from you. I did write a review of the Doge 7 Tube DAC back in 2018. With respect to ordering from Doge, everything went smoothly for me and I had no complaints. (yes, I live in the Ottawa area) Now it is possible that the Covid situation has had some impact of their operations so I would suggest that you ask them directly what the situation is before placing an order.
Enjoy your music,
Roger McCuaig

Caps data
Dear TNT,
how does one calculate the speed V/uS for capacitors? I noticed this in this TNT-Audio article and I am interested in comparing and the equation would be appreciated. For bass applications, would it matter for the slew rate to get higher than 50V/uS?
Trevor - E-mail: tvormittiag (at)

I cannot find any data or info about capacitor speed in terms of V/us values. The values you find on high quality caps data sheets (for example are ESR equivalent series resistance Rated ripple current. ESR is easy to understand: in capacitor models there always is some resistance due to leads, electrodes and other inner components impedence: this is what is limiting the current in a capacitor (at least at audio frequencies), and is therefore directly correlated to speed.
However, a capacitor subject to a high current flow heats up, so you must limit the current if you want to assure a reasonable life time to a cap (
Calculations of speed and current in a given configuration, however, are not so simple, the only solution is simulation of the circuit (
This requires an appropriate simulation model ( for a discussion of a proper model) and a simulation environment (LTSpice or similar).
Hope this helps,
Giorgio Pozzoli

Clarifications about TNT AIRCOIL
Hello Roger,
First of all, thank you for the information, tips and articles that you wrote on TNTaudio, they are always interesting and useful!
I am writing to you to have some clarification about the cable in question, the TNT AIRCOIL, actually I followed the project that you described, in order to create an RCA - JACK3.5 cable to be able to connect a DAP to the integrated amplifier (an excellent example of NAD3020i whose tone I love), in my opinion, and without still making resistance and capacitance measurements, this cable sounds good, is neutral and transparent and has a lot of dynamics.
The comparison, by ear, is with the homemade TNT SHIELD cable. As conductors I used an AWG23 of a CAT6, but I did not find information on either the quality of the copper or the type of insulation. The cable is made up of two conductors for each channel (one for heat and one for cold) which are intertwined alternately in a single Teflon tube. On the RCA side, on the other hand, I adopted two pieces of Teflon for each channel and twisted to 2.
My explanations:

I apologize for the inconvenience caused, and for my poor school English (thank goodness that google translate exists ... hehehe) and above all for any wrong written information, I am a novice of audiophile environment, but I am trying to document and learn.
Thank you in advance, let me know if something is not really clear.
Best regards,
Dimitri - E-mail: skadym (at)

Hi Dimitri,
Thanks for your email. I have used both CAT5E and CAT6 cables as sources for the conductors used to build my Aircoil projects. I always try to find "Plenum Rated" cable as this means that the conductor insulation will be Teflon and not HDPE.(high density polyethylene) Teflon has a better dielectric constant. (less electric charge is stored in the insulation) Now there are certainly some people who would argue that, in this application, the difference is so tiny that it is of no consequence, and they may be right. My reasoning is simply that the cost difference is very small (in some cases I got the cable for free!) so why not use the Teflon insulated conductors. I did read someplace that CAT5E and CAT6 cable are made with 99% pure copper, however, I certainly wouldn't claim that to be an absolute truth. One thing is known, CAT6 UTP (Unshielded Twisted Pair) is capable of transmitting data at 250 MHz so our 20 KHz audio signal is not a challenge.
With respect to your cable design I'm sorry to say that I have not been able to fully understand your description so I will have to abstain from any comment on that. Maybe you could send me a sketch of photos?
Now for the noise problem associated with unplugging the cable from the DAP, well, this is quite common and the best advice that I can give you is never leave a cable connected to an amplifier or preamp input with nothing connected to the source end. It's not a good practice.
Enjoy your music,
Roger McCuaig

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